Humic acid derivatives and methods of preparation and use

ABSTRACT

Disclosed are antioxidative natural compounds, their salts, chelates and cleavage derivatives that exhibit a superior combination of properties. The compounds can be used for a variety of purposes, including the stabilization of polymers. The compounds can be prepared by substantially cleaving a humic acid of formula I followed by esterification to provide at least one antioxidant compounds of formula V, formula VI, formula VII, formula VIII, salts thereof, or chelates thereof.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a U.S. national stage filing under 35 U.S.C. §371 ofInternational Application No. PCT/US2013/042814 filed on May 28, 2013entitled “HUMIC ACID DERIVATIVES AND METHODS OF PREPARATION AND USE,”which is incorporated herein by reference in its entirety.

BACKGROUND

Polymers and their composites are the essential materials used in foodpackaging, medical applications, children toys, teaching aids and otherconsumer goods. Processing of polymers to the final products by allavailable technologies require using several types of additives such asstabilizers, plasticizers, fillers, anti-slippage, anti-static chargesand others.

The plastics industry is searching for natural additives such asstabilizers, plasticizer, antistatic charges and antioxidants tostabilize polymers used in food packaging and the other applicationsmentioned above to replace the currently used anti-oxidants like BHT(butylated hydroxy toluene), TBHQ (tertiary butylhydroquinone), BHA(butylated hydroxyl anisole) and synthetic plasticizers such as DOP(dioctyl phthalate).

SUMMARY

New antioxidants for use in food packaging, medical applications,children's toys and teaching aids are ideally non-toxic as they are indirect contact with humans, inexpensive, effective at lowconcentrations, and able to survive processing such as injection, blow,extrusion or film production. The additives in the finished products canbe non-volatile, anti-static and devoid of undesirable color, flavor,and odor effects. The additives can also be compatible with ubiquitouspolymer and can be multi-functional additives such as stability effect;being a thermal stabilizer, antioxidant, plasticize, anti -slippage, andanti-static at the same time.

This disclosure details a natural source of inexpensive additives thatcan be used in food packaging as well as other applications where theplastic materials are in direct contact with humans or other animals.The additives disclosed may function as stabilizers, antioxidants,plasticizers, and/or convey anti-static properties to the end product.The additives are at least inspired by or based on humic acid, itscleaved products and their derivatives such as salts and chelates as amulti-activity stabilizer, antioxidant, chain breaking, free radicalscavenger, HCL acceptor for PVC and its copolymers, and an activeplasticizer with possible links with aseptic ingredients.

It has been found that subjecting humic acid to selective aryl ethercleavage conditions followed by esterification and chelate formationcreates compounds that meet at least one, and sometimes many or all theabove described criteria for polymer additives. The stabilization,plasticization and antistatic efficiency of these sustainable naturalproducts and their derivatives is due to their chemical structure whichcontains all functional groups that are known as antioxidants, freeradical scavengers active groups plus having synergistic characteristicsvia o,p-quinone-hydroquinone structures, HCl deactivating agents for PVCvia metal chelates, promising plasticizing agents in addition of beingantistatic agents (which prevents dust accumulation) due to high polarphenolic hydroxyl and ester groups. The natural ingredient (humic acid)is currently produced on an industrial scale for various applications.The low molecular weight structures obtained from cleavage of humic acidhave tremendous potential as stabilizers, anti-oxidant/thermalstabilizers, plasticizers for various polymer systems, particularlyfood-safe polymeric packaging, medical applications and children toys,due to their high stabilization efficiency, high decompositiontemperature, non-volatility, non-leachability and high chemicalstability, natural source, cheap and non-toxic.

The stabilizing compounds are ester derivatives of humic acid I, orester derivatives of hydrolysis products II, III, and IV of humic acidI. The esters are alkyl esters or substituted alkyl esters of thecarboxylic acid moieties of humic acid, or the fatty esters orsubstituted fatty esters of phenol moieties of humic acid as esters V,VI, VII, and VIII. Various embodiments include chelates and salts of theester derivatives.

The polymer stabilizing compounds can be prepared by substantiallyhydrolyzing humic acid to form a mixture of compounds and esterifying atleast one functional group of the mixture of compounds to give a polymerstabilizing mixture of compounds. Embodiments of the method furthercomprise formation of chelates or salts of the compounds. Otherembodiments further comprise purification of one or more of the estercomponents.

Polymeric matrices comprise at least one of the polymer stabilizingcompounds. In certain embodiments, the polymeric matrix can be ofpolyvinyl chloride, low density polyethylene, high density polyethylene,polyvinyl alcohol, polypropylene, or a combination thereof. Thepolymeric matrix can be used in a food packaging, nutritional productpackaging, beverage packaging, toy, medical packaging, or cosmeticpackaging.

DETAILED DESCRIPTION

The above summary of the present technology is not intended to describeeach illustrated embodiment or every possible implementation of thepresent technology. The detailed description, which follows,particularly exemplifies these embodiments.

Before the present compositions and methods are described, it is to beunderstood that they are not limited to the particular compositions,methodologies or protocols described, as these may vary. It is also tobe understood that the terminology used in the description is for thepurpose of describing the particular versions or embodiments only, andis not intended to limit their scope which will be limited only by theappended claims.

It must also be noted that as used herein and in the appended claims,the singular forms “a”, “an”, and “the” include plural reference unlessthe context clearly dictates otherwise. Unless defined otherwise, alltechnical and scientific terms used herein have the same meanings ascommonly understood by one of ordinary skill in the art. Although anymethods and materials similar or equivalent to those described hereincan be used in the practice or testing of embodiments disclosed, thepreferred methods, devices, and materials are now described.

The term “alkyl” or “alkyl group” refers to a branched or unbranchedhydrocarbon or group of 1 to 20 carbon atoms, such as but not limited tomethyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, octyl,decyl, tetradecyl, hexadecyl, eicosyl, tetracosyl and the like.“Cycloalkyl” or “cycloalkyl groups” are branched or unbranchedhydrocarbons in which all or some of the carbons are arranged in a ring,such as but not limited to cyclopentyl, cyclohexyl, methylcyclohexyl andthe like. The term “lower alkyl” includes an alkyl group of 1 to 6carbon atoms.

“Substituent” refers to a molecular non-toxic group that replaces ahydrogen in a compound and may include, but is not limited to, C₁-C₂₀alkyl. The term “substituted alkyl” is used herein to allow for thepresence of one or more additional substituents on an alkyl group.

“Optional” or “optionally” means that the subsequently described eventor circumstance may or may not occur, and that the description includesinstances where the event occurs and instances where it does not.

The term “halide” as used herein refers to the halogens fluorine,chlorine, bromine, and iodine.

“Substantially no” means that the subsequently described event may occurat most about less than 10% of the time or the subsequently describedcomponent may be at most about less than 10% of the total composition,in some embodiments, and in others, at most about less than 5%, and instill others at most about less than 1%.

As used herein the term “transition metal” should be understood toinclude elements that are non-toxic non heavy metals or radioactive ofthe Periodic Table. In chemical terms, these are elements having apartially filled inner shell of electrons. The term “transition metalchelate” as used herein generally means a transition metal cation andanions that surround the metal cation and are joined to it byelectrostatic bonds.

As used herein, the term “stereoisomer” refers to a compound made up ofthe same atoms bonded by the same bonds but having differentthree-dimensional structures which are not interchangeable.

Humic acid having chemical structure (I), wherein

-   -   R₁₁ is —N(R₁₁₁)(R₁₁₂), wherein R₁₁₁ is C-acetamido or        substituted C-acetamido; R₁₁₂ is hydrogen, —(C₁-C₂₀)alkyl,        substituted —(C₁-C₂₀)alkyl, —(C═O)—(C₃-C₁₉)alkyl, or substituted        —(C═O)—(C₃-C₁₉)alkyl;    -   R₁₂ is hydrogen, —(C₁-C₂₀)alkyl, or substituted —(C₁-C₂₀)alkyl;    -   R₁₃ is hydrogen, —(C₁-C₂₀)alkyl, substituted —(C₁-C₂₀)alkyl,        —(C═O)—(C₃-C₁₉)alkyl, or substituted —(C═O)—(C₃-C₁₉)alkyl; and    -   R₁₆ is a hydrogen, glucuronate or substituted glucuronate,    -   has cleavable groups at C1-C4.

Hydrolysis of aryl heteroatom bonds C1—C4 of humic acid I leads tocompounds II-IV. The compounds are active multi pH buffers since theydissolve at all pH values. The cleavage derivatives of humic acid at oneor more of C1—C4, and their carboxylate salts and chelates have lowermolecular weight than humic acid. These derivatives also have highoxygen content due to carboxylate groups adjacent to carbonyl orhydroxyl groups.

salt, or chelate thereof, wherein

-   -   R₂ is hydrogen, —(C₁-C₂₀)alkyl, or substituted —(C₁-C₂₀)alkyl;        and    -   R₄ is hydrogen, —(C₁-C₂₀)alkyl, or substituted —(C₁-C₂₀)alkyl.

Polymer stabilizing compounds may be prepared as ester derivatives ofhumic acid I, or ester derivatives of hydrolysis products II, III, andIV of humic acid I. The esters are alkyl esters or substituted alkylesters of the carboxylic acid moieties, or the fatty esters orsubstituted fatty esters of phenol moieties of humic acid.

In an aspect, the stabilizing compound is an ester of at least one offormulas V-VIII:

-   -   R₂ is hydrogen, —(C₁-C₂₀)alkyl, or substituted —(C₁-C₂₀)alkyl;    -   R₄ is hydrogen, —(C₁-C₂₀)alkyl, or substituted —(C₁-C₂₀)alkyl;    -   R₁₁ is —N(R₁₁₁)(R₁₁₂), wherein R₁₁₁ is C-acetamido or        substituted C-acetamido; R₁₁₂ is hydrogen, —(C₁-C₂₀)alkyl,        substituted —(C₁-C₂₀)alkyl, —(C═O)—(C₃-C₁₉)alkyl, or substituted        —(C═O)—(C₃-C₁₉)alkyl;    -   R₁₂, R₁₄₁, R₁₄₂, R₁₄₃, and R₁₄₄, are independently hydrogen,        —(C₁-C₂₀)alkyl, or substituted —(C₁-C₂₀)alkyl;    -   R₁₃ is hydrogen, —(C₁-C₂₀)alkyl, substituted —(C₁-C₂₀)alkyl,        —(C═O)—(C₃-C₁₉)alkyl, or substituted —(C═O)—(C₃-C₁₉)alkyl;    -   R₁₆ is a hydrogen, glucuronate or substituted glucuronate;    -   R₂₁, R₂₂, R₃₁, R₃₂, and R₄₁ are independently hydrogen,        —(C₄-C₂₀)alkyl, or substituted —(C₄-C₂₀)alkyl;    -   R₂₃, R₂₄, R₂₅, R₂₆, R₂₇, R₃₃, R₃₄, R₃₅, R₃₆, R₄₂, R₄₃, and R₄₄        are independently hydrogen, —(C═O)—(C₃-C₁₉)alkyl, or substituted        —(C═O)—(C₃-C₁₉)alkyl; and    -   R₁₅₁, R₁₅₂, R₁₅₃, R₁₅₄, R₁₅₅, and R₁₅₆ are independently        hydrogen, —(C═O)—(C₃-C₁₉)alkyl, or substituted        —(C═O)—(C₃-C₁₉)alkyl; and    -   wherein at least one of R₁₄₁, R₁₄₂, R₁₄₃, R₁₄₄, R₁₅₁, R₁₅₂,        R₁₅₃, R₁₅₄, R₁₅₅, and R₁₅₆ is not hydrogen; at least one of R₂₁,        R₂₂, R₂₃, R₂₄, R₂₅, R₂₆, and R₂₇ is not hydrogen; at least one        of R₃₁, R₃₂, R₃₃, R₃₄, R₃₅, and R₃₆, is not hydrogen; and at        least one of R₄₁, R₄₂, R₄₃, and R₄₄ is not hydrogen;    -   a salt, chelate, or combination thereof.

An embodiment is a compound wherein the compound is at least onechemical formula of VI-VIII, salt, chelate, or combination thereof.

One embodiment is at least one compound with formula V-VIII, wherein thecompound is a salt. In another embodiment, the salt is a lithium salt,sodium salt, ammonium salt, potassium salt, calcium salt, barium salt,magnesium salt, manganese salt, zinc salt, aluminum salt, iron salt, ora combination thereof. In yet another embodiment, the salt is a sodiumsalt, potassium salt, calcium salt, or ammonium salt. In still anotherembodiment the compound is a polyvalent cation chelate. In anotherembodiment, the chelate is a calcium, magnesium, iron, or zinc chelateor combination thereof.

Another embodiment is a compound wherein the compound is of chemicalformula of VI, salt, chelate, or combination thereof, wherein:

-   -   R₂ is hydrogen, —(C₁-C₂₀)alkyl, or substituted —(C₁-C₂₀)alkyl;    -   R₂₁, R₂₂, are independently hydrogen, —(C₄-C₂₀)alkyl, or        substituted —(C₄-C₂₀)alkyl;    -   R₂₃, R₂₄, R₂₅, R₂₆, and R₂₇, are independently hydrogen,        —(C═O)—(C₃—C₁₉)alkyl, or substituted —(C═O)—(C₃-C₁₉)alkyl; and    -   wherein at least one of R₂₁, R₂₂, R₂₃, R₂₄, R₂₅, R₂₆, and R₂₇ is        not hydrogen.        Another embodiment is the compound wherein R₂ is hydrogen or        —(C₁-C₂₀)alkyl. In certain embodiments, R₂ is methyl. In other        embodiments, R₂₁, R₂₂, are independently hydrogen or        —(C₄-C₂₀)alkyl. In other embodiments, wherein R₂₃, R₂₄, R₂₅,        R₂₆, and R₂₇, are independently hydrogen or        —(C═O)—(C₃-C₁₉)alkyl; and wherein at least one of R₂₁, R₂₂, R₂₃,        R₂₄, R₂₅, R₂₆, and R₂₇ is not hydrogen.

Another embodiment is at least one compound of formula VI, wherein thecompound is a salt. In another embodiment, the salt is a lithium salt,sodium salt, ammonium salt, potassium salt, calcium salt, barium salt,magnesium salt, manganese salt, zinc salt, aluminum salt, iron salt, ora combination thereof. In yet another embodiment, the salt is a sodiumsalt, potassium salt, calcium salt, or ammonium salt. In still anotherembodiment, at least one compound of formula VI is a polyvalent cationchelate. In another embodiment, the chelate is a calcium, magnesium,iron, or zinc chelate or combination thereof.

Another embodiment the compound has formula VII, salt, chelate, orcombination thereof, wherein

-   -   R₃₁, R₃₂, are independently hydrogen, —(C₄-C₂₀)alkyl, or        substituted —(C₄-C₂₀)alkyl;    -   R₃₃, R₃₄, R₃₅, and R₃₆, are independently hydrogen,        —(C═O)—(C₃-C₁₉)alkyl, or substituted —(C═O)—(C₃-C₁₉)alkyl; and    -   wherein at least one of R₃₁, R₃₂, R₃₃, R₃₄, R₃₅, and R₃₆ is not        hydrogen.        Another embodiment is the compound wherein further R₃₁ and R₃₂,        are independently hydrogen or —(C₄-C₂₀)alkyl, and wherein at        least one of R₃₁, R₃₂, R₃₃, R₃₄, R₃₅, and R₃₆ is not hydrogen.        Another embodiment is the compound wherein R₃₃, R₃₄, R₃₅, and        R₃₆ are independently hydrogen or —(C═O)—(C₃-C₁₉)alkyl, and        wherein at least one of R₃₁, R₃₂, R₃₃, R₃₄, R₃₅, and R₃₆ is not        hydrogen.

Another embodiment is at least one compound of formula VII, wherein thecompound is a salt. In another embodiment, the salt is a lithium salt,sodium salt, ammonium salt, potassium salt, calcium salt, barium salt,magnesium salt, manganese salt, zinc salt, aluminum salt, iron salt, ora combination thereof. In yet another embodiment, the salt is a sodiumsalt, potassium salt, calcium salt, or ammonium salt. Still anotherembodiment is at least one compound of formula VII, wherein the compoundis a polyvalent cation chelate. In another embodiment, the chelate is acalcium, magnesium, iron, or zinc chelate or combination thereof.

An embodiment is a compound wherein the compound is of chemical formulaof VIII, salt, chelate, or combination thereof, wherein

-   -   R₄ is hydrogen, —(C₁-C₂₀)alkyl, or substituted —(C₁-C₂₀)alkyl;    -   R₄₁ is independently hydrogen, —(C₄-C₂₀)alkyl, or substituted        —(C₄-C₂₀)alkyl;    -   R₄₂, R₄₃, and R₄₄ are independently hydrogen,        —(C═O)—(C₃-C₁₉)alkyl, or substituted —(C═O)— (C₃-C₁₉)alkyl; and    -   wherein at least one of R₄₁, R₄₂, R₄₃, and R₄₄ is not hydrogen.        Another embodiment is the compound wherein further R₄ is        hydrogen or —(C₁-C₂₀)alkyl. A certain embodiment is wherein R₄        is methyl. Another embodiment is wherein R₄₁ is hydrogen or        —(C₄-C₂₀)alkyl, and wherein at least one of R₄₁, R₄₂, R₄₃, and        R₄₄ is not hydrogen. Still another embodiment is wherein R₄₂,        R₄₃, and R₄₄ are independently hydrogen or —(C═O)—(C₃-C₁₉)alkyl,        and wherein at least one of R₄₁, R₄₂, R₄₃, and R₄₄ is not        hydrogen.

Another embodiment is at least one compound of formula VIII, wherein thecompound is a salt. In another embodiment, the salt is a lithium salt,sodium salt, ammonium salt, potassium salt, calcium salt, barium salt,magnesium salt, manganese salt, zinc salt, aluminum salt, iron salt, ora combination thereof. In yet another embodiment, the salt is a sodiumsalt, potassium salt, calcium salt, or ammonium salt. Still anotherembodiment is at least one compound of formula VIII, wherein thecompound is a polyvalent cation chelate. In another embodiment, thechelate is a calcium, magnesium, iron, or zinc chelate or combinationthereof.

Another aspect is a method to prepare a stabilizing compound from humicacid. A representative humic acid (I):

-   -   salt, or chelate thereof, wherein    -   R₁₁ is —N(R₁₁₁)(R₁₁₂), wherein R₁₁₁ is C-acetamido or        substituted C-acetamido;    -   R₁₁₂ is hydrogen, —(C₁-C₂₀)alkyl, substituted —(C₁-C₂₀)alkyl,        —(C═O)—(C₃-C₁₉)alkyl, or substituted —(C═O)—(C₃-C₁₉)alkyl;    -   R₁₂ is hydrogen, —(C₁-C₂₀)alkyl, or substituted —(C₁-C₂₀)alkyl;    -   R₁₃ is hydrogen, —(C₁-C₂₀)alkyl, substituted —(C₁-C₂₀)alkyl,        —(C═O)—(C₃-C₁₀)alkyl, or substituted —(C═O)—(C₃-C₁₉)alkyl; and    -   R₁₆ is a hydrogen, glucuronate or substituted glucuronate.    -   Is cleaved at C1-C4 to give cleavage products (II-IV):

-   -   salt, or chelate thereof, wherein    -   R₂ is hydrogen, —(C₁-C₂₀)alkyl, or substituted —(C₁-C₂₀)alkyl;        and    -   R₄ is hydrogen, —(C₁-C₂₀)alkyl, or substituted —(C₁-C₂₀)alkyl.        Humic acid I and cleavage products II-IV are contacted with an        agent to give fatty acid esters V-VIII.

-   -   salt, or chelate thereof, wherein    -   R₁₁ is —N(R₁₁₁)(R₁₁₂), wherein R₁₁₁ is C-acetamido or        substituted C-acetamido; R₁₁₂ is hydrogen, —(C₁-C₂₀)alkyl,        substituted —(C₁-C₂₀)alkyl, —(C═O)—(C₃-C₁₉)alkyl, or substituted        —(C═O)—(C₃-C₁₉)alkyl;    -   R₁₂, R₁₄₁, R₁₄₂, R₁₄₃, and R₁₄₄ are independently hydrogen,        —(C₁-C₂₀)alkyl, or substituted —(C₁-C₂₀)alkyl;    -   R₁₃ is hydrogen, —(C₁-C₂₀)alkyl, substituted —(C₁-C₂₀)alkyl,        —(C═O)—(C₃-C₁₀)alkyl, or substituted —(C═O)—(C₃-C₁₉)alkyl;    -   R₁₅₁, R₁₅₂, R₁₅₃, R₁₅₄, R₁₅₅, and R₁₅₆ are independently        hydrogen, —(C═O)—(C₃-C₁₀)alkyl, or substituted        —(C═O)—(C₃-C₁₉)alkyl; and    -   R₁₆ is a hydrogen, glucuronate or substituted glucuronate;    -   wherein at least one of R₁₄₁, R₁₄₂, R₁₄₃, R₁₄₄, R₁₅₁, R₁₅₂,        R₁₅₃, R₁₅₄, R₁₅₅, and R₁₅₆ is not hydrogen;

-   -   R₂ is hydrogen, —(C₁-C₂₀)alkyl, or substituted —(C₁-C₂₀)alkyl;    -   R₄ is hydrogen, —(C₁-C₂₀)alkyl, or substituted —(C₁-C₂₀)alkyl;    -   R₂₁, R₂₂, R₃₁, R₃₂, and R₄₁ are independently hydrogen,        -(C₄—C₂₀)alkyl, or substituted —(C₄-C₂₀)alkyl;    -   R₂₃, R₂₄, R₂₅, R₂₆, R₂₇, R₃₃, R₃₄, R₃₅, R₃₆, R₄₂, R₄₃, and R₄₄        are independently hydrogen, —(C═O)—(C₃-C₁₉)alkyl, or substituted        —(C═O)—(C₃-C₁₉)alkyl; and    -   wherein at least one of R₂₁, R₂₂, R₂₃, R₂₄, R₂₅, R₂₆, and R₂₇ is        not hydrogen, at least one of R₃₁, R₃₂, R₃₃, R₃₄, R₃₅, and R₃₆,        is not hydrogen, and at least one of R₄₁, R₄₂, R₄₃, and R₄₄ is        not hydrogen.

In another embodiment the compound has a formula V. In anotherembodiment, the compound has a formula VI. In yet another embodiment,the compound has a formula VII. In still another embodiment, thecompound has a formula VIII.

In the various embodiments, the agent is a reactive fatty acidequivalent, wherein at least one aryl alcohol forms an alkyl ester. Insome embodiments, the fatty acid equivalent is an acid chloride. Inother embodiments, the fatty acid equivalent is an anhydride. In stillother embodiments, the fatty acid is an activated ester. In certainembodiments, the alkyl ester formed is a —(C═O)—(C₃-C₁₉)alkyl fattyester.

In the various embodiments, the agent is an alcohol, wherein at leastone carboxylic acid functionality forms an alkyl ester. In someembodiments, the carboxylic acid is activated as an acid chloride. Inother embodiments, the carboxylic acid is activated as an anhydride. Instill other embodiments, the carboxylic acid is an activated ester. Inyet other embodiments, the carboxylic acid is esterified general acid orbase catalysis. In still other embodiments, the alkyl ester is from atransesterification. In certain embodiments, the alkyl ester formed is a—(C₄-C₂₀)alkyl ester.

In the various embodiments, the agent is a first agent and a secondagent. In some embodiments, the first agent is an alcohol as above and asecond agent is a reactive fatty acid equivalent as above.

In each of the embodiments, the method can further comprise making atleast one salt or chelate of the compounds. In an embodiment of thesalts, the method comprises making a lithium salt, sodium salt, ammoniumsalt, potassium salt, calcium salt, barium salt, magnesium salt,manganese salt, zinc salt, aluminum salt, iron salt, or a combinationthereof. In yet another embodiment, the method comprises making a sodiumsalt, potassium salt, calcium salt, or ammonium salt. In an embodimentof the chelates, the method comprises making a polyvalent cationchelate. In another embodiment, the method comprises making a calcium,magnesium, iron, or zinc chelate or combination thereof.

In another embodiment, the method can further comprise isolating atleast one compound of formula V-VIII, salt, chelate, or combinationthereof. Isolation can include, but is not limited to, filtration,decantation, phase separation, distillation, centrifugation,evaporation, or combinations thereof.

In another embodiment, the method can further comprise purifying atleast one compound of formula V-VIII, salt, chelate, or combinationthereof. Purification can include, but is not limited to, steamdistillation, distillation, crystallization, reverse phasechromatography, normal phase chromatography, precipitation, refining,sublimation, evaporation, extraction, absorption, washing, orcombinations thereof.

In various embodiments the humic acid I may be cleaved at positions C1,C2, C3, and C4 by action of a hydrogenolysis cleaving agent.Hydrogenolysis cleaving agents can include, but are not limited tonickel—Catalyzed hydrogenolysis, sodium borohydride (NaBH₄), amide hydrohalide salts, lithium chloride in dimethylformamide, hydrogen iodide,and hydrogen bromide, and others.

In various embodiments the hydrolysis is carried out in an alkalinesolution. In some embodiments, the alkaline solution is an aqueousalkaline hydroxide, or mixtures thereof. In some embodiments, thealkaline solution is aqueous lithium hydroxide, aqueous sodiumhydroxide, aqueous potassium hydroxide, or combination thereof. Incertain embodiments, the alkaline solution is aqueous sodium hydroxide.In various embodiments, the hydrolysis is performed at a pH of about 8,about 8.5, about 9, about 10, about 11, about 12, about 13, about 14, orat a pH range between or at any of the two pH values. In variousembodiments, the hydrolysis is performed with heat. In certainembodiments, the hydrolysis is performed at reflux temperatures.

Still another aspect is a polymeric matrix comprising at least onestabilizing compound of formula V-VIII:

-   -   wherein R₂ is hydrogen, —(C₁-C₂₀)alkyl, or substituted        —(C₁-C₂₀)alkyl;    -   R₄ is hydrogen, —(C₁-C₂₀)alkyl, or substituted —(C₁-C₂₀)alkyl;    -   R₁₁ is —N(R₁₁₁)(R₁₁₂), wherein R₁₁₁ is C-acetamido or        substituted C-acetamido; R₁₁₂ is hydrogen, —(C₁-C₂₀)alkyl,        substituted —(C₁-C₂₀)alkyl, —(C═O)—(C₃-C₁₉)alkyl, or substituted        —(C═O)—(C₃-C₁₉)alkyl;    -   R₁₂, R₁₄₁, R₁₄₂, R₁₄₃, and R₁₄₄ are independently hydrogen,        —(C₁-C₂₀)alkyl, or substituted —(C₁-C₂₀)alkyl;    -   R₁₃ is hydrogen, —(C₁-C₂₀)alkyl, substituted —(C₁-C₂₀)alkyl,        —(C═O)—(C₃-C₁₉)alkyl, or substituted —(C═O)—(C₃-C₁₉)alkyl;    -   R₁₆ is a hydrogen, glucuronate or substituted glucuronate;    -   R₂₁, R₂₂, R₃₁, R₃₂, and R₄₁ are independently hydrogen,        -(C₄-C₂₀)alkyl, or substituted —(C₄-C₂₀)alkyl;    -   R₁₅₁, R₁₅₂, R₁₅₃, R₁₅₄, R₁₅₅, and R₁₅₆ are independently        hydrogen, —(C═O)—(C₃-C₁₉)alkyl, or substituted        —(C═O)—(C₃-C₁₉)alkyl; and    -   R₂₃, R₂₄, R₂₅, R₂₆, R₂₇, R₃₃, R₃₄, R₃₅, R₃₆, R₄₂, R₄₃, and R₄₄        are independently hydrogen, —(C═O)—(C₃—C₁₉)alkyl, or substituted        —(C═O)—(C₃-C₁₉)alkyl; and    -   wherein at least one of R₁₄₁, R₁₄₂, R₁₄₃, R₁₄₄, R₁₅₁, R₁₅₂,        R₁₅₃, R₁₅₄, R₁₅₅, and R₁₅₆ is not hydrogen; at least one of R₂₁,        R₂₂, R₂₃, R₂₄, R₂₅, R₂₆, and R₂₇ is not hydrogen; at least one        of R₃₁, R₃₂, R₃₃, R₃₄, R₃₅, and R₃₆, is not hydrogen; and at        least one of R₄₁, R₄₂, R₄₃, and R₄₄ is not hydrogen; salt, or        chelate thereof;    -   in combination with a polymer.

In an embodiment the compound is at least one compound of formulaVI-VIII. In another embodiment the compound has a formula V. In anotherembodiment, the compound has a formula VI. In yet another embodiment,the compound has a formula VII. In still another embodiment, thecompound has a formula VIII.

Embodiments include a polymeric matrix comprising at least oneantioxidant compound of formula V-VIII, a salt, or chelate thereof, incombination with a polymer. In certain embodiments, the polymer is apolyvinyl chloride, low density polyethylene, high density polyethylene,polyvinyl alcohol, polypropylene, or combination thereof. In yet otherembodiments, the polymeric matrix may be suitable for various packagingto extend a shelf life of a product. In certain embodiments, thepolymeric matrix is a food packaging, nutritional product packaging,beverage packaging, toy, medical packaging, or cosmetic packaging.

In yet another embodiment, the antioxidant compound is present in thepolymeric matrix by weight at a concentration of about 5%, about 2.5%,about 1%, about 0.5%, about 1000 ppm, about 300 ppm, about 200 ppm,about 100 ppm, about 30 ppm, about 10 ppm, about 3 ppm, about 1 ppm, orany range between two of the concentrations. In various specificembodiments, the antioxidant is present in a polymer at less than about5000 ppm, less than about 300 ppm, less than about 100 ppm, or less thanabout 10 ppm. In certain embodiments, the antioxidant compound isbetween about 0.02% and about 2.5% by weight of the polymer. In anothercertain embodiment, the antioxidant compound is between about 0.1% andabout 0.5% by weight.

In each of the aforementioned embodiments of the polymeric matrix, theantioxidant compound may be a salt. In certain embodiments, the salt isa lithium salt, sodium salt, ammonium salt, potassium salt, calciumsalt, barium salt, magnesium salt, manganese salt, zinc salt, aluminumsalt, iron salt, or a combination thereof. In certain embodiments, thesalt is a sodium salt, potassium salt, calcium salt, ammonium salt, orcombination thereof. In an embodiment, the antioxidant compound is asodium salt. In another embodiment, the antioxidant compound is apotassium salt. In yet another embodiment, the antioxidant compound is acalcium salt. In still another certain embodiment, the antioxidantcompound is an ammonium ion salt. In yet other embodiments of theaforementioned antioxidant compounds, the antioxidant compound may be apolyvalent chelate. In certain embodiments, the transition metal ionchelate is a magnesium chelate, calcium chelate, zinc chelate, ironchelate, or combination thereof.

The chelates of fatty ester products V-VIII are particularly suitable asHCl deactivators for PVC and its copolymers. The chelates can react withHCl formed from the thermal decomposition of PVC. The role of HCl iswell known to accelerate the thermal decomposition of PVC (accordinglyPVC stabilizers consist of HCl deactivators (Scheme 1):

In some embodiments, the fatty ester products V-VIII can be transferredto master batch pellets which can be added to any thermoplastic orelastomers during their processing to the final packaging products.Master batch is a technical method to improve distribution andhomogenization of the additives within a polymeric matrix. In a masterbatch, most of the active ingredients, except the plasticizers, used insmall composition ratios such as colorants, stabilizers, antistaticmaterials and other additives are extruded with a high melt indexpolymer, for example, either same polymer or from other compatiblepolymers, and then transferred to a pellet form that which can be easilymixed with the required basic polymer and processed to the finalproducts.

The fatty ester products V-VIII represent ideal structures as antistaticadditives which are essential additives usually added to most polymersin order to prevent the accumulation of dusts on the surface of thepackaged items such as: toys, medical packaging and appliances andcosmetics which accordingly, leave the surface clean of dust. Theefficiency of these materials as anti-static additives is based on theconcept that preventing static charge accumulation, by either usingconductive materials such as quaternary ammonium salts or by usingcompounds with highly polar groups that are capable of forming hydrogenbonding or having electrolyte characteristics. The new naturalderivatives described in this disclosure possess the characteristicswhich make packing anti-static: that being they consist of metalchelates and have free hydroxyl groups that form strong hydrogenbonding.

The fatty ester products V-VIII are very efficient multi-functionalplasticizing additives and are highly suitable to replace the currentlyused phthalate plasticizers due to the current global health issuessurrounding these plasticizers. The advantage of the new natural basedplasticizers over the phthalate plasticizers is that they are non-toxicand based on aromatic structures which give them enhanced compatibilitywith most common polymers used in thermoplastic industry for packaging.They possess extremely high boiling point and thus are almostnon-volatile, and have high molecular weight which leads them to benon-migratable, non-leachable, and have high thermal stability. In otherwards it has almost all the requirement of plasticizers for variousapplications with the added advantage of being non-toxic and food gradeas the starting materials are based on natural food ingredient.

A typical esterification reaction of the phenolic groups present in thenatural humic antioxidant cleavage product and fatty carboxylic acidssuch as octanoic acid, iso-octanoic acid, butanoic acid, decanoic acid,or other carboxylic acids with alkyl groups containing: C₄ to C₂₀.Typical esterification reaction of the carboxylic acids, carboxylic acidanhydride or acid chlorides with phenolic groups present in the naturalantioxidant and fatty alcohols such as butyl alcohol, pentyl, hexyl,heptyl, cetyl, to C₂₀. The same reactions can be applied to humic acidI, and its cleavage derivatives II-IV to prepare mono, di, tri, or oligoester groups, and as partially chelated with suitable metal ions.

Cleavage of aryl heteroatom bonds C1-C4 of humic acid I leads tocompounds II-IV. The compounds are active multi pH buffers since theydissolve at all pH values. The cleavage derivatives of humic acid at oneor more of C1-C4, and their carboxylate salts and chelates have lowermolecular weight than humic acid. These derivatives also have highoxygen content due to carboxylate groups adjacent to carbonyl orhydroxyl groups.

Humic acid cleavage derivatives can be obtained by a reductive cleavagetechnique. Chemical compounds V-VIII, have active functional groups(quinones, hydroquinones and alkyl phenols) that can act asanti-oxidants and free radical scavengers, chelating groups (viacarboxyl groups or hydroxyl groups). The chemical compounds V-VIII areless expensive to manufacture than ascorbic acid and have the ability todissolve and bond minerals and other nutritional elements with enhancedbioavailability.

The anti-oxidation efficiency of these sustainable, natural derivativesis due to their chemical structure which contains functional groups thatare known as antioxidants and free radical scavenger active groups.Humic acid as a basic ingredient for the proposed technology iscurrently extracted on industrial scale mainly for use as organicfertilizers and plant nutrients. It is sourced cheaply fromnon—Contaminated marsh and forest soils that can contain up to 30-40%humic materials. Furthermore, these compounds have tremendous potentialas thermal stabilizers for various polymer systems used in foodpackaging.

The cleavage derivatives of humic acid I have various uses including asantioxidants for several polymeric systems such as polyvinyl chloride(PVC), polyethylene (PE) and polypropylene (PP). These antioxidants canbe used as a solid, solution, chelated with transition (nutrient)metals. The carboxylic acid group can be transformed into carboxylatesalts of Na, K, Ca, Zn, Mg, and can form chelates with divalent andtrivalent metal ions. The low molecular weight structures deriveddemonstrate a higher efficiency as anti-oxidants than humic acid I, andthe chemical compounds V-VIII have tremendous potential asanti-oxidant/thermal stabilizers for various polymer systems,particularly food-safe polymeric packaging.

The antioxidants of embodiments from cleavage of humic acid typicallyrequire no necessary purification steps, such as ultrafiltration ordesalination, nor fractionation into fractions with distinct molecularweights and high purity. The crude antioxidant cleavage solutionunexpectedly, and advantageously, exhibits high activity without anyfurther costly processing. However, purified compounds, their salts,chelates, and cleavage derivatives can potentially exhibit superiorcharacteristics in certain applications.

Consumer interest in and awareness of the health properties ofantioxidants has been increasing in recent years. This hassimultaneously increased global sales of antioxidants (whether used as afood preservative or to provide a health enhancing or functionalbenefit) and foods that are recognized as being naturally rich inantioxidants. As the sector has developed, antioxidants are now beingused in the manufacture of a greater variety of goods to cater forincreasingly health—Conscious consumers.

The humic acid derivatives are more efficient (based on humic acidstudies) and cost effective compared to all other plasticizers andstabilizers. Humic acid derivatives and cleavage derivatives would becheaper to manufacture than ascorbic acid and synthetic antioxidants andhave greater thermal stability convenient for almost all food processingand cooking up to 350° C. and have the ability to dissolve and bondminerals and other nutritional elements with enhanced bioavailability.

EXAMPLES

Although the present technology has been described in considerabledetail with reference to certain embodiments thereof, other versions arepossible. Therefore the spirit and scope of the appended claims shouldnot be limited to the description and versions contained within thisspecification. The various aspects of the present technology will beillustrated with reference to the following non-limiting examples.

Example 1 Cleavage of Humic Acid Using Sodium Hypophosphite and HydrogenIodide

Humic acid was extracted from non-polluted marsh soils with an organiccontent of 30-35%. The alkaline extracted humic acid from marsh soils orforests soils was suspended in 25-40% HI solution in a stoichiometricequivalent ratio to the ether groups of humic acid weight ratio of 1:10.The humic acid underwent cleavage in the presence of sodiumhypophosphite (10% of the HI) added to prevent further iodination of thearomatic phenolic structures and prevents oxidation of iodine ions.

The reaction mixture was heated to reflux. The humic acid suspensionbegan to cleave after 45 minutes and the solution became colored. Thecolor changed progressively with reflux time. Fractions were taken at 15minute intervals until all the humic acid suspension disappears(approximately after 10 hours depending on the concentration of HI)until a homogeneous reaction mixture was obtained.

Fraction products were neutralized or transferred to the carboxylatesalts (Na, Ca, Mg, Mn, and similar salts) by neutralizing the carboxylicacid groups with required alkaline hydroxides or carbonate.

The reaction matrix compositions mixture were characterized by TLC (ThinLayer Chromatography), pH titration, IR, NMR and molecular weightdetermination for some of the fractions.

The TLC displayed at least 12 spots using different solvent carriers,indicating the presence of at least 12 compounds in the final reactionmixture. This was in good agreement with the chemical structureevaluation in addition of presence of low aromatic carboxylic acids andhydroquinone derivatives.

Example 2a Cleavage of Humic Acid Using Nickel Catalysis

The cleavage of bonds of Example 1 may be performed by nickel catalyzedhydrogenolysis. The humic acid is dissolved in 3-octenone or othersolvents or mixed solvents in the presence of nickel carbine complexunder one bar of hydrogen at a temperature of 80-120° C. The reactionproduces a mixture of compounds II-IV.

Example 2b Cleavage of Humic Acid Using Sodium Borohydride

The cleavage of bonds of Example 1 may be performed by action of sodiumborohydride. Humic acid is dissolved in a solution of sodium hydroxidein 1:1 ethanol:water in the presence of Ni—Cr-boride where sodiumborohydride is formed in situ. The reaction takes place at atmosphericpressure. The reaction produces a mixture of compounds II-IV.

Example 2c Cleavage of Humic Acid Using Lithium Chloride

The cleavage of bonds of Example 1 may be performed by action of lithiumchloride in dimethyl formamide. Humic acid is dissolved in a solution ofLiCl-DMF at boiling conditions for 4-72 hours. The reaction produces amixture of compounds II-IV.

Example 2d Cleavage of Humic Acid Using Hydrogen Iodide

The cleavage of bonds of Example 1 may be performed by action ofhydrogen iodide. The humic acid is reacted with aqueous hydrogen iodideand sodium hypophosphite to form a suspension. Alternatively, thesuspension is heated until a substantially homogeneous reaction mixtureis obtained. In yet another alternative, the heating is carried out atreflux temperature. The reaction produces a mixture of compounds II-IV.

Example 2e Cleavage of Humic Acid Using Hydrogen Bromide

The cleavage of bonds of Example 1 were performed by action of hydrogenbromide. Humic acid was dissolved in an organic solvent such as methylethyl ketone or a mixture of solvents, and then this mixture was addedto an aqueous solution consisting of glacial acetic acid andconcentrated hydrogen bromide at 0-10° C. in the presence of 1%surfactant (Cetrimide). The cleavage was carried out in an emulsionsystem under efficient mixing for 5 hours. At the end of five hours, thetemperature was raised to 25° C. The reaction was continued for anadditional hour. The reaction produced a mixture of compounds II-IV.

Example 3a Esterification of Compounds II-IV Phenols to Give Mixed NonylEsters

Mixed acetic-nonanoic anhydride 12.5 gm is added to a 250 ml stirredflask and 0.95 gm of a mixture of compounds II-IV from any one ofExamples 1 and 2a-2e and 0.13 gm sulphuric acid added to the anhydrideto form a mobile dispersion. This is heated to 90-100° C. and maintainedat this temperature for 3 hours before cooling to 40° C. and dispersionin 200 ml of ethanol or petroleum ether. After filtration orconcentration the solid is subjected to two further washes before beingdried and analyzed to give a yield of 80% of mixed nonyl aryl esters ofcompounds II-IV.

Example 3b Esterification of Compound IV Phenols to Give Trinonyl EsterVIII

Mixed acetic-nonanoic anhydride 12.5 gm is added to a 250 ml stirredflask and 3.74 gm2-(2,7,8-trihydroxy-1,4-dioxo-1H-phenoxazin-10(4H)-yl)propanoic acid(IV, R=Me) and 0.13 gm sulphuric acid added to the anhydride to form amobile dispersion. This is heated to 90-100° C. and maintained at thistemperature for 3 hours before cooling to 40° C. and dispersion in 200ml of ethanol or petroleum ether. After filtration or concentration thesolid is subjected to two further washes before being dried and analyzedto give a yield of 80% of the trinonyl aryl esters of compound IV.

Example 3c Esterification of Compounds II-IV Carboxylic Acids to GiveMixed Esters

One kg of a mixture of compounds II-IV, 1872 gm of decyl alcohol (12mol), and 0.59 gm of tetra butyl titanate are weighed into a 4 literdistillation flask with a Dean-Stark-trap and reflux condenser, andheated to boiling under nitrogen. The water of reaction produced duringthe esterification is regularly removed. After about 3 hours the excessalcohol is distilled off under vacuum. The mixture is cooled to 80° C.and transferred to a 4 liter reaction flask with immersion tube,dropping funnel, and column. A sodium hydroxide solution (5 weight %) isthen used for neutralization. The mixture is then heated under vacuum(10 mbar) to 190° C. Deionized water is then added drop-wise via thedropping funnel, at constant temperature. After addition of the water,the heating is switched off and the mixture is cooled. The mixed estersare filtered with a filtration aid to give a mixture of decyl carboxylicesters of compounds VI-VIII.

Example 3d Esterification of Compound IV Carboxylic Acid to Give DecylEster

Compound IV (100 gm), 187 gm of decyl alcohol, and 0.06 gm of tetrabutyl titanate are weighed into a 500 mL distillation flask with aDean-Stark-trap and reflux condenser, and heated to boiling undernitrogen. The water of reaction produced during the esterification isregularly removed. After about 3 hours excess alcohol is distilled offunder vacuum. The mixture is cooled to 80° C. and transferred to a 500mL reaction flask with immersion tube, dropping funnel, and column Asodium hydroxide solution (5 weight %) is then used for neutralization.The mixture is then heated under vacuum (10 mbar) to 190° C. Deionizedwater is then added drop-wise via the dropping funnel, at constanttemperature. After addition of the water, the heating is switched offand the mixture is cooled. The mixed esters are filtered with afiltration aid to form the decyl carboxylic ester of compound VIII.

Example 4a Preparation of the Calcium Chelates of a Mixture of DecylEsters of Compounds VI-VIII

Calcium oxide (5.6 gm) and 65 gm of the decyl esters of compoundsVI-VIII (Example 3c) were placed into a flask provided with a refluxcondenser. Ethanol (100 mL) was added and the mixture was stirred andboiled at atmospheric pressure for 5 hours. The reaction mixture wasthen cooled, and thereafter filtered yielding 65 grams of calciumchelate of the decyl esters having the physical characteristic of a finewhite powder.

Example 4b Preparation of the Magnesium Chelate of Decyl Ester ofCompound VIII

4.0 grams (0.1 Mole) of magnesium oxide and 65 grams (0.2 Mole) of thedecyl ester of compound VIII (Example 3d) were placed into a flaskprovided with a reflux condenser. Ethanol (100 mL) was added and themixture was stirred and boiled at atmospheric pressure for 5 hours. Thereaction mixture was then cooled, and thereafter filtered yielding 60grams of calcium chelate of the decyl ester of compound VIII having thephysical characteristic of a fine white powder.

Example 4c Preparation of the Zinc Chelate of Decyl Ester of CompoundVII

Zinc hydroxide is placed in a flask with a reflux condenser and 100grams of the decyl ester of compound VII. Ethanol is added and themixture boiled for 3 hours. The mixture is cooled and filtered yielding100 gm of the zinc chelate of the decyl ester of compound VII.

Example 5 Stability Data

The mixture of the calcium chelate of compounds of formula V, VI, VII,and VIII prepared in Example 4, were evaluated as antioxidants andthermal stabilizers for PVC, low density polyethylene, and polyvinylalcohol as a model to evaluate the anti-oxidation efficiency usingthermal analysis (differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)) techniques, including differentialthermogravimetry (DTG) to determine the decomposition temperature. Thechelates with several transition metal ions showed remarkable efficiencyfor thermo-oxidative stabilization of PVC. Typical results are providedin Table (1). Tests using 1% of the calcium salt of the hydrolyzedhumate mixture in extruded PVC show higher stabilizing efficiency than1% of humic acid in extruded PVC. Both were better than PVC extrudedwithout an antioxidant.

TABLE (1) Thermal degradation stability of PVC and stabilized PVCs HCl %(loss) from TGA PVC with +1% PVC with Ca-chelate of PVC control 1% Humica mixture of V, Temperature, ° C. (K value 70) acid VI, VII, and VIII250 3 1 0 260 5 2 0 270 10 2 0.5 280 33 5 1.0 290 1 13 1.0 300 47 35 5.0Total HCl loss (%) 63 57 53 at Decomp. Temp. Decomp. Temp., ° C., 265280 310 from DTG Rate of decomposition 1.63 1.09 0.73 at Decomp. Temp.%/min

Example 6 Stabilization of Polyethylene for Food Packaging:

Polyethylene films are prepared with 0.1% by weight and with 0.5% byweight of a mixture of the calcium chelate of compounds of formula V,VI, VII, and VIII prepared in Example 4 by extrusion methods to formfilms for food packaging. The films are subjected to natural sun lightin Sydney, Australia, and with high UV light for 4 weeks. The resultantfilms are tested by IR and UV spectrometry. The films stabilized withmetal chelates show no color change and no spectral changes, whileunstabilized polyethylene samples as controls show change in colorationand absorption spectra.

Example 7 Stabilization of Polyvinyl Chloride (PVC) for Food Packaging:

PVC (K value 70) stabilized with 1% of a mixture of the calcium chelateof compounds of formula V, VI, VII, and VIII prepared in Example 4(typical thermal stability characteristics listed in Table 1) areprepared by extrusion to form films for food packaging. The films aresubjected to natural sunlight in Sydney, Australia, and with high UVlight for 4 weeks. The stabilized films with metal chelates show nocolor change while control films of unstabilized PVC samples show changein coloration to a dark yellowish color.

What is claimed is:
 1. A stabilizing compound comprising a compound offormula V:

wherein R₁₁ is —N(R₁₁₁)(R₁₁₂), wherein R₁₁₁ is C-acetamido orsubstituted C-acetamido; R₁₁₂ is hydrogen, —(C₁-C₂₀)alkyl, substituted—(C₁-C₂₀)alkyl, —(C═O)—(C₃-C₁₉)alkyl, or substituted-(C═O)—(C₃-C₁₉)alkyl; R₁₂, R₁₄₁, R₁₄₂, R₁₄₃, and R₁₄₄ are independentlyhydrogen, —(C₁-C₂₀)alkyl, or substituted —(C ₁-C₂₀)alkyl; R₁₃ ishydrogen, —(C₁-C₂₀)alkyl, substituted —(C₁-C₂₀)alkyl,—(C═O)—(C₃-C₁₉)alkyl, or substituted —(C═O)—(C₃-C₁₉)alkyl; R₁₆ is ahydrogen, glucuronate or substituted glucuronate; R₁₅₁, R₁₅₂, R₁₅₃,R₁₅₄, R₁₅₅, and R₁₅₆ are independently hydrogen, —(C═O)—(C₃-C₁₉)alkyl,or substituted —(C═O)—(C₃-C₁₉)alkyl, wherein at least one of R₁₄₁, R₁₄₂,R₁₄₃, R₁₄₄, R₁₅₁, R₁₅₂, R₁₅₃, R₁₅₄, R₁₅₅, and R₁₅₆ is not hydrogen; asalt, chelate, or combination thereof.
 2. The compound of claim 1,wherein the compound is a salt thereof.
 3. The compound of claim 1,wherein R₁₄₁, R₁₄₂, R₁₄₃, and R₁₄₄ are independently hydrogen or—(C₄-C₂₀)alkyl.
 4. The compound of claim 1, wherein R₁₅₁, R₁₅₂, R₁₅₃,R₁₅₄, R₁₅₅, and R₁₅₆ are independently hydrogen or —(C═O)—(C₃-C₁₉)alkyl.5. The compound of claim 1, wherein the compound is a lithium salt,sodium salt, ammonium salt, potassium salt, calcium salt, barium salt,magnesium salt, manganese salt, zinc salt, aluminum salt, iron salt, ora combination thereof.
 6. The compound of claim 1, wherein the compoundis a polyvalent cation chelate.
 7. The compound of claim 1, wherein thecompound is a calcium chelate, magnesium chelate, iron chelate, or zincchelate or combination thereof.
 8. A method of preparing a polymerstabilizing mixture of compounds, the method comprising: substantiallyhydrolyzing a humic acid to form a mixture of compounds according toformula V a salt or chelate thereof:

wherein: R₁₁ is —N(R₁₁₁)(R₁₁₂), wherein R₁₁₁ is C-acetamido orsubstituted C-acetamido; R₁₁₂ is hydrogen, —(C₁-C₂₀)alkyl, substituted—(C₁—C₂₀)alkyl, —(C═O)—(C₃-C₁₉ alkyl, or substituted—(C═O)—(C₃-C₁₉)alkyl; R₁₂, R₁₄₁, R₁₄₂, R₁₄₃ and R₁₄₄ are independentlyhydrogen, -(C₄—C₂₀)alkyl, or substituted —(C₄-C₂₀ alkyl; R₁₃ ishydrogen, —(C₁-C₂₀ alkyl, substituted —(C₁-C₂₀)alkyl, —(C═O)—(C₃—C₁₉)alkyl, or substituted —(C═O)—(C₃-C₁₉)alkyl; R₁₆ is hydrogen,glucuronate, or substituted glucuronate; R₁₅₁, R₁₅₂, R₁₅₃, R₁₅₄, R₁₅₅,and R₁₅₆ are independently hydrogen, —(C═O)—(C₃-C₁₉)alkyl, orsubstituted —(C═O)—(C₃-C₁₉)alkyl; R₁₄₁, R₁₄₂, R₁₄₃, R₁₄₄, R₁₅₁, R₁₅₂,R₁₅₃, R₁₅₄, R₁₅₅, and R₁₅₆ are hydrogen; and esterifying at least onefunctional group of the mixture of compounds to give a polymerstabilizing mixture of compounds.
 9. The method of claim 8, furthercomprising forming a chelate of the compound of the polymer stabilizingmixture with a calcium cation, magnesium cation, zinc cation, ironcation, or combinations thereof.
 10. The method of claim 8, furthercomprising forming a salt of the compound of the polymer stabilizingmixture to form a lithium salt, sodium salt, ammonium salt, potassiumsalt, calcium salt, barium salt, magnesium salt, manganese salt, zincsalt, aluminum salt, iron salt, or a combination thereof.
 11. The methodof claim 8, further comprising purifying the compound of the polymerstabilizing mixture.
 12. The method of claim 8, further comprisingisolating the compound of formula V wherein at least one of R₁₄₁, R₁₄₂,R₁₄₃, R₁₄₄, R₁₅₁, R₁₅₂, R₁₅₃, R₁₅₄, R₁₅₅, and R₁₅₆ is not hydrogen; atleast one of R₂₁, R₂₂, R₂₃, R₂₄, R₂₅, R₂₆, and R₂₇ is not hydrogen; atleast one of R₃₁, R₃₂, R₃₃, R₃₄, R₃₅, and R₃₆ is not hydrogen; and atleast one of R₄₁, R₄₂, R₄₃, and R₄₄ is not hydrogen.
 13. The method ofclaim 8, wherein the humic acid comprises at least one compound offormula I:

salt, or chelate thereof, wherein R₁₁ is —N(R₁₁₁)(R₁₁₂), wherein R₁₁₁ isC-acetamido or substituted C-acetamido; R₁₁₂ is hydrogen,—(C₁—C₂₀)alkyl, substituted —(C₁-C₂₀)alkyl, —(C═O)—(C₃-C₁₉)alkyl, orsubstituted —(C═O)—(C₃—C₁₉)alkyl; R₁₂ is hydrogen, —(C₁-C₂₀)alkyl, orsubstituted —(C₁-C₂₀)alkyl; R₁₃ is hydrogen, —(C₁-C₂₀)alkyl, substituted—(C₁-C₂₀)alkyl, —(C═O)—(C₃-C₁₉)alkyl, or substituted—(C═O)—(C₃-C₁₉)alkyl; and R₁₆ is a hydrogen, glucuronate or substitutedglucuronate.
 14. The method of claim 8, wherein the hydrolyzingcomprises hydrolyzing in the presence of an alkaline solution.
 15. Themethod of claim 14, wherein the alkaline solution is aqueous lithiumhydroxide, aqueous sodium hydroxide, aqueous potassium hydroxide, orcombination thereof.
 16. The method of claim 8, wherein the hydrolyzingcomprises hydrolyzing at a pH of 8.5-13.